Thryonomys Research Articles

Diversity of hunting fauna affected by hunting in the savannah region of northern Côte d'Ivoire

Meat from wild animals, commonly known as bushmeat, has always been a significant source of protein for many households in Côte d'Ivoire and other tropical regions of the world. However, population growth in recent decades, improved hunting methods and increased demand for bushmeat have intensified the burden on wildlife through the profits derived from its marketing. In the Bandama Valley, Savannah and Denguélé districts, there are a limited number of scientific studies on hunting and the animal species involved in game trafficking. The aim of this research is to provide wildlife managers with information on the particular diversity of game fauna in the study districts, with a view to promoting sustainable management. In order to achieve this objective, weekly inventories of game offered for sale in markets and restaurants in the districts visited were carried out. In all, 4,356 specimens were counted, divided into three classes, 12 orders, 22 families and 36 animal species. Among these species, the small-scaled pangolin (Manis tricuspis), the Gabon viper (Bitis gabonica), the dwarf crocodile (Osteolaemus tetraspis) and the tortoise (Kinixys belliana) are among those in danger of extinction. In terms of abundance of specimens, mammals make up the largest number, with 77.41% of species identified. The Greater Cane Rat (Thryonomys swinderianus), is the species most killed with 1392 individuals or 31.96% of the total number of specimens inventoried. This work is helping to perfect and extend sustainable natural resource management strategies.

Study of the natural habitats of the great grasscutter (Tryonomys swinderianus TEMINK, 1827) with a view to its conservation in situ at Sangarédi, Boké prefecture

The Sangarédi area, located in the prefecture of Boké, has vegetation essentially composed of tree and shrub savannah, the natural biotope of the great grasscutter. Today, this vegetation is under serious threat from human activity, with mining companies exploiting large areas, thereby destroying the environment. This state of affairs has contributed to a reduction in the habitat of this animal, which is highly prized by the local population. The aim of the study was to contribute to the identification, location and characterisation of the habitats of the great grasscutter in Lower Guinea, with a view to its conservation in situ. A questionnaire was drawn up and applied to a sample of 260 individuals in 3 selected localities in the Sangarédi sub-prefecture. The results of this study revealed forest galleries and fallow land in which the great grasscutter is found. 54 sites were identified. The existence of the cane rat was confirmed in five (5) habitat types. In situ conservation of natural habitats is one of the safest alternatives for preserving the grasscutter.

Greater cane rat algorithm (GCRA): A nature-inspired metaheuristic for optimization problems

This paper introduces a new metaheuristic technique known as the Greater Cane Rat Algorithm (GCRA) for addressing optimization problems. The optimization process of GCRA is inspired by the intelligent foraging behaviors of greater cane rats during and off mating season. Being highly nocturnal, they are intelligible enough to leave trails as they forage through reeds and grass. Such trails would subsequently lead to food and water sources and shelter. The exploration phase is achieved when they leave the different shelters scattered around their territory to forage and leave trails. It is presumed that the alpha male maintains knowledge about these routes, and as a result, other rats modify their location according to this information. Also, the males are aware of the breeding season and separate themselves from the group. The assumption is that once the group is separated during this season, the foraging activities are concentrated within areas of abundant food sources, which aids the exploitation. Hence, the smart foraging paths and behaviors during the mating season are mathematically represented to realize the design of the GCR algorithm and carry out the optimization tasks. The performance of GCRA is tested using twenty-two classical benchmark functions, ten CEC 2020 complex functions, and the CEC 2011 real-world continuous benchmark problems. To further test the performance of the proposed algorithm, six classic problems in the engineering domain were used. Furthermore, a thorough analysis of computational and convergence results is presented to shed light on the efficacy and stability levels of GCRA. The statistical significance of the results is compared with ten state-of-the-art algorithms using Friedman's and Wilcoxon's signed rank tests. These findings show that GCRA produced optimal or nearly optimal solutions and evaded the trap of local minima, distinguishing it from the rival optimization algorithms employed to tackle similar problems. The GCRA optimizer source code is publicly available at: https://www.mathworks.com/matlabcentral/fileexchange/165241-greater-cane-rat-algorithm-gcra.

Antibiofilm Potential of Aqueous Extracts of Garcinia kola against ‎Salmonella species in Greater Cane Rat (Thryonomys swinderianus, ‎Temmink 1827) from Badagry, Lagos State, Nigeria

Biofilms encompass a cluster of microorganisms encased in a slimy matrix of extracellular polymeric substances, which imbibe antibiotic resistance. Salmonella specie is a major bacterial cause of food-borne diseases in both humans and animals. The prevalence of Salmonella species is increasing which may form biofilm, and bacteria that form biofilm may be more resistant to antimicrobial agents. This study is intended to determine the presence and antimicrobial susceptibility patterns of Salmonella species among greater cane rats and carry out the biofilm formation of isolated Salmonella species and dispersion using Garcinia kola. A total of 20 cane rats were obtained from a farm in Lagos state and roadside hunters. Samples of rectal swabs were collected aseptically for bacterial culture. Bacteria isolation was done with selective media using standard bacteriological techniques following pre-enrichment of the samples with buffered peptone water. Gram staining and biochemical tests were used for confirmation of the organisms. An antimicrobial susceptibility test was performed following standard protocol. Zones of inhibition were measured and categorized as totally sensitive and resistant. Nine (9) isolates of Salmonella species were obtained from rectal swabs of greater cane rats. A modified crystal violet assay was employed to develop biofilm and test the effect of a crude extract of Garcinia kola on biofilm dispersal. Data obtained from this study was subjected to statistical analysis using descriptive statistics and paired t-test at a level of significance of P ≤ 0.05. The overall prevalence of Salmonella species obtained in this study was 45%. Antimicrobial study showed susceptibility of 77.8% for Chloramphenicol and 66.7% for Cefuroxime while all isolates were 100% susceptible to Amikacin and Gentamicin. The effect of Garcinia kola extract on different isolates at 430nm showed a significant difference (p= 0.0348) in biofilm formation in isolates with Garcinia kola extract when compared with isolates without extract. The effect of Garcinia kola extract on different isolates at 650nm elicited significant (p = 0.0216) biofilm inhibitions across the isolates. The antibiofilm activity displayed by Garcinia kola suggests its potential to serve as an alternative antimicrobial agent to combat drug resistant bacteria such as Salmonella species. However, further investigations should be carried out on the individual bioactive compounds to know the exact metabolites responsible for the antibiofilm activity of this bacteria species.

Wild animal trade in Cameroon: An insight into species involved and conservation implications in the western Highlands

Abstract Illegal bushmeat trade is a significant driver of the decline in wildlife populations within the tropics. Despite the intense trade of bushmeat in Cameroon, there is dearth or no official statistics on the kind of animals sold in the markets in most parts of Cameroon. To abridge this knowledge gap, an inventory of wild animals sold in local markets was carried out. The animal taxa sold within the markets were identified, and their abundance, class diversity and conservation status according to the IUCN Red List of threatened species and Cameroon wildlife classification were assessed. Semi‐structured questionnaires were randomly administered to 200 traders randomly selected in 16 markets. Multivariate analyses were used to compare the proportions of sold taxa among the markets and the proportions of taxa based on their conservation status. Results were summarized as shown below: (1) 476 individuals of animals were recorded, covering 47 taxa, 41 genera, 33 families, 18 orders and 3 classes from bushmeat vendors. (2) Mammals dominated the trade in all markets (by a mean of 74.3% per market), followed by reptiles (16.1%) and birds (9.5%) in terms of both abundance and diversity. (3) Cane rats (Thryonomyidae) and primates (Cercopithecidae) represented the highest proportions of animal specimens recorded. (4) The diversity of mammals sold was highest in Foumbot, followed by Bangangte, Bafousam and Bangoua as the main local markets, and lowest mammalian diversity was found in Batcham and Baham village markets. (5) The most often traded animal species belonged to the least concern category, followed by vulnerable, near threatened, endangered, and critically endangered. In general, we observed that less protected species by the IUCN Red List and Cameroon wildlife classification were often found in village markets and species with higher conservation value were often sold in city markets. Similarly, the main markets hosted the highest diversity of sold animals, especially mammals. The size of the human settlement together with its location nearby protected area and/or placement of the market by the main road are the main drivers determining numbers and diversity of sold animals, and further attention to government conservation activities should be focused on these markets.

Radiological Anatomy of the Pelvis and Pelvic Limb of the Greater Cane Rat (Thryonomys swinderianus).

Greater cane rats (Thryonomys swinderianus) are now being captive reared and domesticated in the sub-Saharan Africa because of increase in their demand for biomedical research and traditional medicine and as a source of meat. This research was performed to provide the normal radiological anatomy of the pelvis and pelvic limb in greater cane rats for a reference in biomedical research, in anatomical studies, and in clinical use. Radiological examination of the pelvis and right pelvic limb was done in five greater cane rats. Radiological results were correlated with bones of the pelvis and right pelvic limb. The pelvic bone had a prominent caudoventral iliac spine. The pelvic symphysis was long and obturator foramina appeared teardrop-shaped elongated craniocaudally. The prominent major trochanter extended proximally higher than the femoral head. The middle third of the body of the tibia presented a very prominent tuberosity. In all specimens, the tarsal sesamoid bone was visualised. Mineralised popliteal sesamoid bone was not visualised. In male greater cane rats, the os penis was visualised. The lateral and medial menisci of the stifle joint were seen with ossicles. The first metatarsal bone was rudimentary with greater plantar divergence. Despite of the pelvic limb and pelvis of greater cane rats sharing anatomical structures with other rodents, it retains some exceptional anatomical features. Findings of this study will serve as a reference for anatomical studies, clinical veterinary practice, and in biomedical research.

Microscopic anatomy of the subcommissural organ in the brain of the adult greater cane rat (Rodentia: Thryonomyidae).

The subcommissural organ (SCO) is a well-developed gland present in the brain of vertebrates. The SCO secretes glycoproteins into the circulating cerebrospinal fluid and these assemble to form Reissner's fibre. It also plays an important function in neurogenesis and axonal guidance during embryogenesis. This study delves into the microscopic anatomy of the SCO in the adult greater cane rat (GCR), shedding light on its histoarchitectural characteristics. By utilizing histological techniques and microscopic analysis, we investigated the SCO's location and cellular composition within the brain of adult GCR. Our findings showed that the SCO in this species is located ventrally to the posterior commissure (PC) and dorsally to the third ventricle. The SCO consists of specialized ependymal or nuclear cell layer and apical processes lining the third ventricle. Moreover, the SCO's proximity to the PC and the third ventricle highlights its strategic position within the brain's ventricular system. With immunohistochemical analyses, the SCO cells expressed glial fibrillary protein when immunolabelled with Glial fibrillary acid protein (GFAP) antibody, a marker for astrocytes/astrocytic-like cells. Few microglia-like cells were immuno-positive for Ionized calcium-binding adapter molecule 1 (Iba1) antibody, that are existing within the SCO. However, the SCO in the GCR showed a negative immunostaining to NeuN antibody. This study contributes to our understanding of the microscopic anatomy of the SCO in a lesser-studied mammalian species. Further research into the SCO's functional significance especially during development in the GCR, may hold promise for more insights into neurological health and pathology.

Neocortex neurogenesis and maturation in the African greater cane rat

BackgroundNeocortex development has been extensively studied in altricial rodents such as mouse and rat. Identification of alternative animal models along the “altricial-precocial” spectrum in order to better model and understand neocortex development is warranted. The Greater cane rat (GCR, Thyronomys swinderianus) is an indigenous precocial African rodent. Although basic aspects of brain development in the GCR have been documented, detailed information on neocortex development including the occurrence and abundance of the distinct types of neural progenitor cells (NPCs) in the GCR are lacking.MethodsGCR embryos and fetuses were obtained from timed pregnant dams between gestation days 50–140 and their neocortex was analyzed by immunofluorescence staining using characteristic marker proteins for NPCs, neurons and glia cells. Data were compared with existing data on closely related precocial and altricial species, i.e. guinea pig and dwarf rabbit.ResultsThe primary sequence of neuro- and gliogenesis, and neuronal maturation is preserved in the prenatal GCR neocortex. We show that the GCR exhibits a relatively long period of cortical neurogenesis of 70 days. The subventricular zone becomes the major NPC pool during mid-end stages of neurogenesis with Pax6 + NPCs constituting the major basal progenitor subtype in the GCR neocortex. Whereas dendrite formation in the GCR cortical plate appears to initiate immediately after the onset of neurogenesis, major aspects of axon formation and maturation, and astrogenesis do not begin until mid-neurogenesis. Similar to the guinea pig, the GCR neocortex exhibits a high maturation status, containing neurons with well-developed dendrites and myelinated axons and astrocytes at birth, thus providing further evidence for the notion that a great proportion of neocortex growth and maturation in precocial mammals occurs before birth.ConclusionsTogether, this work has deepened our understanding of neocortex development of the GCR, of the timing and the cellular differences that regulate brain growth and development within the altricial–precocial spectrum and its suitability as a research model for neurodevelopmental studies. The timelines of brain development provided by this study may serve as empirical reference data and foundation in future studies in order to model and better understand neurodevelopment and associated alterations.

Isolating Greater Cane Rat Populations (Thryonomys swinderianus) from Eastern Arc Mountains, Tanzania: Linking Diversity to Morphometric and Molecular Characteristics

Evolutionary information on the greater cane rat (Thryonomys swinderianus) in the Eastern and Southern African regions is scarce, making population management and conservation of the species challenging. We studied T. swinderianus populations from two spatially isolated Eastern Arc Mountains in Tanzania to link molecular and geometric–morphological evidence to characterize these populations’ diversity. Fecal samples (n = 50) and skulls (n = 99) of T. swinderianus were collected from Udzungwa (north and south) and Uluguru mountains (urban and rural sites) and analyzed using molecular and geomorphometry techniques. Molecular analysis grouped the population into three distinct clades based on the location where the samples were collected, while the morphometric method was not able to distinctively separate the populations. Both methods revealed that the population obeyed the isolation by distance model with higher genetic distance between the Udzungwa and Uluguru populations and lower distance between Uluguru urban and rural populations. Both Mahalanobis and Procrustes distances in skull landmarks between the Udzungwa and Uluguru populations were significantly higher across the dorsal, ventral, and lateral views of the skulls, suggesting strongly that molecular and morphometric methods applied together can be useful in characterizing the population traits of the least known species. Our study suggests genetic and morphometric methods could complement each other in understanding the evolutionary biology and within-species diversity of vertebrate species that do not exhibit strong intra-species differentiation.

Comparative Analysis of Sperm Quality of the Greater Cane Rat (Thryonomys swinderianus) Collected by Masturbation and Epididymal Puncture, in Côte d'Ivoire

Comparative Analysis of Sperm Quality of the Greater Cane Rat (Thryonomys swinderianus) Collected by Masturbation and Epididymal Puncture, in Côte d'Ivoire

A novel binary greater cane rat algorithm for feature selection

There is a surge in the application of population-based metaheuristic algorithms to find the optimal feature subset from high dimensional datasets. Many of these approaches cannot properly scale especially as they are expected to maintain two opposing goals: maximizing the accuracy of classification while at the same time minimizing the number of feature subsets selected. In this study, a novel binary greater cane rat algorithm (GCRA), inspired by intelligent nocturnal behavior of the GCR which significantly affects their foraging and mating activities. They leave trails to food sources, shelters, and water as they forage, and this information is kept by the dominant. Also, they split into male and female groups during mating season is during abundant food supply and near water source. This information is modeled into and effective method for selecting the optimal feature subset from high-dimensional datasets using two different approaches. Firstly, five variants of binary GCRA are developed using one each from the family of S-shaped, V-shaped, U-shaped, Z-shaped, and quadratic transfer functions to binarize the GCRA. Secondly, the threshold which maps a variable to 0 or 1 is used to develop a variant of GCRA. The performance of the six (6) variants were evaluated using 12 datasets with different dimensionalities. The experimental results show the stability of all the proposed methods as they generally performed competitively. However, the threshold version known as BGCRA showed better performance in yielding the highest accuracy of classification on 9 of the 12 datasets utilized in the study and performed second in selecting the least number of important feature sets. It also showed superiority over other variants in yielding the least average fitness values in 11 of 12 (91.6%) of the datasets used. Hence, the BGCRA was utilized for further comparative analysis against 5 other popular feature selection (FS) algorithms with outstanding performance in terms of producing the highest mean accuracy of classification on 91.6% (11 of 12) of the datasets, 100% least average fitness values, and 91.6% in selecting the least average number of significant features. The results were also validated by statistical tests which showed that the BGCRA is significantly superior compared to other methods.

Phylogeographic Patterns of the Greater Cane Rat (Thryonomys Swinderianus) Populations from Eastern, Western and Southern Africa and Implications for Wildlife Conservation

Background and aim: African Greater Cane (ACG) rat populations are widely distributed across Africa but the ancestral origin of populations inhabiting different geographical regions is unknown. There is currently no information available on the genetic differentiation of these populations resulting from long-time geographical isolation, environmental and anthropogenic pressures they face in each region. This limits our ability to understand potential speciation processes in AGC and their implications for their conservation and of other small wild mammals exposed to similar ecological conditions in the savannah biomes in Africa. Methods: We analyzed mitochondrial genes targeting the D-loop region of AGC samples from two blocks of the Eastern Arc Mountains in Tanzania (eastern), three agro-ecological zones in Ghana (western) and four sites in South Africa (southern) to characterize the phylogeographical patterns of the species. Results: AGC populations from Tanzania revealed higher haplotype diversity than those from the two other régions. Analysis of variance (AMOVA) revealed higher genetic variations within than between populations in all geographic regions. Demographic history analysis revealed a negative and significant Tajima’s D for a single southern African population as well as close relatedness with the Eastern Africa populations, suggesting a common ancestral origin. Conclusion: This is the first study to compare maternal lineages of AGC populations from eastern, western and southern Africa and provides a basis for future genetic studies of the species, its evolutionary ecology and the conservation of these populations across their range. Conservation implications: Evidence of recent population size expansion underpinned by high genetic diversity observed in the Uluguru urban (Tanzania) Guinea savannah (Ghana) and Kwazulu Natal (South Africa) populations suggest that the AGC populations are not currently threatened, consistent with the current IUCN status. Also, the distinct haplotypes observed in each region suggest that the populations can be managed as meta-populations, thus providing opportunities for potential local game-farming programs.

Population structure and evolutionary history of the greater cane rat (Thryonomys swinderianus) from the Guinean Forests of West Africa.

Grasscutter (Thryonomys swinderianus) is a large-body old world rodent found in sub-Saharan Africa. The body size and the unique taste of the meat of this major crop pest have made it a target of intense hunting and a potential consideration as a micro-livestock. However, there is insufficient knowledge on the genetic diversity of its populations across African Guinean forests. Herein, we investigated the genetic diversity, population structures and evolutionary history of seven Nigerian wild grasscutter populations together with individuals from Cameroon, Republic of Benin, and Ghana, using five mitochondrial fragments, including D-loop and cytochrome b (CYTB). D-loop haplotype diversity ranged from 0.571 (± 0.149) in Republic of Benin to 0.921 (± 0.013) in Ghana. Within Nigeria, the haplotype diversity ranged from 0.659 (± 0.059) in Cross River to 0.837 (± 0.075) in Ondo subpopulation. The fixation index (FST), haplotype frequency distribution and analysis of molecular variance revealed varying levels of population structures across populations. No significant signature of population contraction was detected in the grasscutter populations. Evolutionary analyses of CYTB suggests that South African population might have diverged from other populations about 6.1 (2.6-10.18, 95% CI) MYA. Taken together, this study reveals the population status and evolutionary history of grasscutter populations in the region.

Risk of Heavy Metal Poisoning From Consuming Grasscutter Digesta in Ghana.

Grasscutter (cane rat/Thryonomys swinderianus) digesta is used as a spice in Ghana. Research shows that heavy metals from the environment may accumulate in the internal organs of grasscutters, which raises concerns about the possible contamination of grasscutter digesta, too, with heavy metals. Although grasscutter meat in Ghana has been described as safe for consumption, information is lacking on the health risks associated with ingesting the digesta. This study, therefore, aimed to assess the knowledge and perceptions of a merchant and a consumer about the safety of ingesting grasscutter digesta and to evaluate potential health risks from exposure to heavy metals from the spice. A total of 12 digesta samples were analyzed to evaluate potential health risks from exposure to Cd, Fe, Hg, and Mn using a Varian AA240FS Atomic Absorption Spectrometer. The levels of Cd, Hg, and Mn were below the detection limit of 0.01 mg/kg digesta. Also, the estimated daily intake of Fe (0.02 mg/kg) was less than the maximum allowable dose recommended by the US EPA (0.7 mg/kg). The hazard indices of Fe for daily and weekly consumption were <1, suggesting that the consumers may be safe from iron poisoning. Because grasscutter digesta is a relatively expensive spice, it is unlikely to be consumed daily by the average Ghanaian. Moreover, if 10 g of digesta is consumed daily, it can be safely ingested about 971 times in a month. Domestication of grasscutters may be a useful approach to monitor their diet and consequently the quality of their digesta.

Multidrug resistant enterohaemorrhagic Escherichia coli serogroups in the faeces of hunted Wildlife, Abeokuta, Nigeria.

Wildlife play significant roles in the dissemination and zoonotic transmission of pathogens. The enterohaemorrhagic Escherichia coli (EHEC) are associated with complicated cases of food-borne illnesses. This study investigated the presence of EHEC serogroups (O26, O45, O103, O145, O91, O111, O128, O121 and O157) in wildlife species: cane rats (Thryonomys swinderianus), royal antelope (Neotragus pygmaeus), African giant rats (Cricetomys gambianus) and waterbuck (Kobus ellipsiprymnus). EHEC and non-EHEC isolates from these wildlife sources were tested for susceptibility to antimicrobial agents. Overall, 127 (83.0 %) of 153 samples yielded E. coli. Nine (5.9%) samples were positive for EHEC belonging to three serogroups as follows; O26 (n=2), O111 (n=2) and O103 (n=5). The EHEC isolates were from cane rats (n=6) and royal antelope (n=3) and possessed virulence-associated genes stx1 (77.8%), stx2 (100.0%), eaeA (100.0%) and hlyA (100.0%). Overall, 127 E. coli isolates showed resistance to ampicillin (99.2%), ceftiofur (90.6%), tetracycline (90.0%), cephalexin (87.4%), cefotaxime (50.4%), streptomycin 42.5%, ceftazidime (41.7%), nalidixic acid (37.0%), ciprofloxacin (43.6%), amoxicillin/clavulanic acid (32.3%), gentamicin (27.6%), sulphamethoxazole/trimethoprim (25.2%), norfloxacin (17.3%) and chloramphenicol (11.0%). The roles of wildlife in the dissemination and transmission of antimicrobial resistant and zoonotic bacteria should not be neglected for effective preventive and control strategies.

Heavy Metals Accumulation in Feaces of Wildlife around Ogun River in Old Oyo National Park, Nigeria

Knowledge of bioaccumulation of heavy metals (HMs) in wildlife of our national parks is poor. This study evaluated wildlife dungs in Old Oyo National Park (OONP) for bioaccumulation of arsenic (As), cadmium (Cd), chromium (Cr), cupper (Cu), lead (Pb), zinc (Zn), nickel (Ni) and cobalt (Co) using standard procedures. Composite dung samples of kob (K), cane rat (KR), crocodile (C), pattas monkey (PM), olive baboon (OB), civet cat (CC) and western hartebeest (WH) were collected along River Ogun. Concentrations were significantly different (α

Osteology and radiographic anatomy of the thoracic limb of the greater cane rat (Thryonomys swinderianus).

The greater cane rat (Thryonomys swinderianus) is mainly distributed in the humid and sub-humid regions of the sub-Saharan Africa. It is believed to be the second largest African rodent. The aim of this study was to describe the normal osteology and radiographic anatomy of the thoracic limb of the greater cane rat as a reference for teaching, clinical use, anatomical studies and biomedical research. Five intact dead greater cane rats were used for radiographic examination. Radiographic findings were correlated with bone specimens. The clavicle was seen in all animals. The scapula was wide with well-developed acromion and coracoid process. The major and minor tubercles did not extend higher than the head of the humerus. The deltoid tuberosity was very prominent. The medial epicondyle was larger than its lateral counterpart, and the supratrochlear foramen was present. The radial tuberosity was further distally located. The ulnar head was well-developed, and the olecranon tuber was square-shaped. The distal physes for the radius and ulna appeared transverse. The carpus had eight bones. The manus presented with five widely spread digits. The first digit was reduced in size and placed such that the dorsal and palmar surfaces face almost medial and lateral, respectively. Additionally, two rudimentary digits were seen. Variations exist in the normal osteology and radiographic anatomy of the thoracic limb in different species. Knowledge of the normal osteology and radiographic anatomy of the thoracic limb of individual species is important for species identification and diagnosis of musculoskeletal diseases involving the thoracic limb.

Cytoarchitecture of greater cane rat (Thryonomys swinderianus) habenulae and mammillary body

This study was conducted to investigate expression of neurons, glia and connective tissue markers in the habenulae and mammillary body of the Greater Cane Rat (GCR) using histological and immunohistochemical techniques. Four apparently healthy males GCR obtained from Lagos Nigeria were used for this experiment. The brains were harvested after perfusion, carefully dissected and post-fixed in 10% neutral-buffered-formalin (NBF) at 40C for 48 hours. Subsequently, tissue sections were prepared and stained using Haematoxylin and Eosin (H&amp;E), Cresyl-violet, ionized calcium-binding-adapter molecule 1 (Iba1; microglia), glial fibrillary acidic protein (GFAP; astrocytes), neuronal nuclei (NeuN; neurons) and collagen type 1 (Collagen1) antibodies. H&amp;E and Cresyl-violet staining showed the neuronal nuclei and their fibres in the habenulae, mammillary body, and pial capsule that surround the mammillary body ventrally. Astrocytes in the habenulae showed positive immunoreaction to anti-GFAP while the mammillary body revealed expression of perivascular astrocytes and capsular astrocytes. Also, in the mammillary body, the perivascular microglia and meningeal microglia in the pial capsule showed immunopositive reaction to anti-Iba1 while the fibres within blood vessels and capsule were immunopositive to collagen type 1 antibody in the same structure. This work has provided the first cytoarchitectural features and clear description of expression of these specific markers in habenulae and mammillary body in the GCR, which are similar to other rodents but with slight variations.

Year-round longitudinal monitoring of a bushmeat market in central-western Côte d’Ivoire: Implication for wildlife conservation

Hunting for bushmeat in the tropics has become a major issue in terms of conservation and human health, especially in western and central Africa. In Côte d’Ivoire, despite a ban on hunting since 1974, the bushmeat trade is widespread. This situation has been exacerbated by the long-term socio-political unrest in Côte d’Ivoire, resulting in the lack of effective protection of protected areas (PAs). Our study was carried out in the central-west Department of Daloa. We conducted standard interviews with the six main traders of the markets to trace the geographical origin of the bushmeat, and quantify the number of animals sold by direct observations twice a week during 52 weeks. We used multiple regression analyses to identify combinations of variables (proportion of animals killed, mean body mass, total biomass, price of carcass, price per body mass) that influenced poaching pressure.A total of 955 carcasses were recorded in the central market of Daloa. This number includes 948 mammals (99 %), six reptiles (0.6 %), and one bird (0.1 %). Rodentia were the most frequently sold taxons by number of individuals (58 %), followed by Artiodactyla (35 %), Carnivora (4 %), and Primates (1 %). Almost half of the game originated from the Department of Zoukougbeu (42 %; N = 404), followed by the Departments of Daloa (29 %; N = 275) and Séguéla (13 %; N = 123). Over 75 % of all the carcasses appearing in the market consisted of greater cane rats and bushbuck. In contrast, over 68 % of the total biomass (23028.75 kg) entering the market was supplied by Bushbuck and Common warthog. Game diversity by catchment area was the highest in Séguéla and Grégbeu and the lowest in Guezon and Maminigui. Our data indicated that hunting was unequally distributed throughout the central-western region of Côte d’Ivoire or markets are unequally provisioned by hunters. Human population density of the catchment areas affected the quantity and the quality of bushmeat observed at the urban market. Increasing hunting pressure in the Departments of Zoukougbeu proximate to the Haut Sassandra forest reserve indicates that the local authority in charge of the surveillance of this reserve has to reinforce its protection to avoid further faunal depletion. Because most of the ungulates and rodents found on the market occur at high density in disturbed habitats, their relative frequencies in the carcasses provisioning the market could be used as indicators of site over-exploitation.

Mitochondrial genetic diversity of the Greater Cane rat (Thryonomys swinderianus) populations from the Eastern Arc Mountains ecosystem, Tanzania.

Management of most herbivorous small mammal species considered to be pests in Africa is still challenging partly because of the paucity of information on their biological traits that would help to manage their destructive impacts. This gap also precludes the potential for tapping species with potential food-value to improving the economy of rural communities through, for example, sustainable game farming programs in Africa. This study investigates the genetic diversity and population demography of the African Greater Cane rat (AGC), a rodent pest of crops and game species inhabiting two isolated blocks of the Eastern Arc Mountains (EAMs), Tanzania to contribute to the species management and conservation. We used non-invasive sampling techniques and DNA sequencing of the D-loop region of MtDNA (515bp) from 46 cane rats (Thryonomys swinderianus) samples to characterize the genetic diversity and structure of the species and potential population threats faced in natural habitats. We found 25 haplotypes:15 from Uluguru and 9 from Udzungwa mountains populations, containing 49 polymorphic regions (32 parsimoniously informative and 17 singleton sites). Haplotype diversity (range: 0.849-0.995) did not differ substantially across populations but the median haplotype diversity for Udzungwa South was overall lower than for other populations. Nucleotide diversity averaged 0.00641, 0.01528, 0.0111 and 0.01313, respectively for Udzungwa South, Udzungwa North, Uluguru Rural and Uluguru Urban, suggesting high genetic diversity within the four populations. Analysis of molecular variance (AMOVA) indicated significantly high genetic differences between the four populations (FST = 0.16, p = 0.00098) whereas neutrality test (FU's Fs) values were negative, indicating historical population expansion. Similarly, the Bayesian skyline analysis indicated a recent demographic expansion suggesting limited bottlenecks in the recent past in this population. Our results show the AGC population in EAMs consists of four distinct populations which have experienced a recent population expansion, especially among the urban population due perhaps to influence of urbanization process that may have favored assisted species movements across the rural-urban landscapes. Future research should focus on understanding impact of geographical isolation on the genetic structure and diversity of this species.